II - DCE FEL ČVUT v Praze

Diagnostic
evaluation
Diagnostics of
digital output
module
Wire break
detection
I/O Modules with Intrinsically-Safe Signals
C79000-G7076-C152-04
When evaluating the diagnostics, a differentiation must be made between
configurable and non-configurable diagnostic messages. In the case of the
configurable diagnostic messages (e.g. short to M), diagnostics is only
signalled when diagnostic evaluation has been enabled by means of
appropriate parameterization (parameter ”diagnostics short to M”).
Non-configurable diagnostic messages are general, i.e. independent of
parameterization.
A diagnostic signal results in a diagnostic interrupt being triggered providing
the diagnostic interrupt has been enabled by way of parameterization.
Irrespective of the parameterization, known module errors always result in
the SF LED or the corresponding channel fault LED lighting irrespective of
the CPU operating status (at POWER ON).
Exception: The SF LED and the corresponding channel fault LED light in
the event of a wire break only when parameterization is enabled.
Table 2-11 provides an overview of the diagnostic messages. Diagnostics is
enabled in STEP 7 (see Tabble 2-10).
The diagnostic information refers to either the individual channels or the
entire module.
Table 2-11 Diagnostic messages of 322; DO 4 x 24V/10mA and
SM 322; DO 4 x 15V/20mA
Diagnostic message Effective range of
diagnostics
M-short-circuit
configurable
Wire break
No load voltage
Channel ggroup p yes y
Module not parameterized
No external auxiliary supply
No internal auxiliary supply
Fuse blown
Watchdog triggered
EPROM error
RAM error
CPU error
A wire break is detected at a current ≤ 0.15 mA.
SIMATIC S7 Ex Digital Modules
Module no
2-21